Intramolecular dehydration of a 1,2-diol to form an epoxide

Steps:

• Recognize CH3CH(OH)CH2OH as propane-1,2-diol, a vicinal diol.
• Conc. H2SO4 protonates one OH group, facilitating loss of water.
• The adjacent OH attacks the carbocation intramolecularly, forming a three-membered oxirane ring.
• Resulting structure is 2-methyloxirane with CH3 on the ring carbon.

Why C is correct:

• C shows the skeletal formula of 2-methyloxirane, the standard product from acid-catalyzed epoxide formation in 1,2-diols.

Why the others are wrong:

• A: Depicts a linear alkene, ignoring cyclization.
• B: Shows a four-membered ring, incorrect for 1,2-diol spacing.
• D: Illustrates a five-membered cyclic ether, requiring 1,4-diol geometry.

Final answer: C